This invention relates generally, as indicated, to an aircraft drain device and, more particularly, to a drain device for removing water from an ice drawer in an aircraft cabin.
Food and drinks are commonly served to passengers and crew while the aircraft is in flight. With particular reference to drinks, and more particularly cold beverages, an aircraft will usually include an ice drawer for supplying ice for the beverage service. An ice drawer typically includes a top compartment containing potable ice and a bottom compartment (e.g., a drain drawer). The compartments are separated by a screen or other porous member to allow water produced by ice melting in the top compartment to drip to the lower compartment. Desirably, a line is provided to drain the melted-ice water from the bottom compartment on a substantially continuous basis to avoid re-freezing and/or leakage.
In an aircraft, draining of liquids is commonly accomplished by directing the waste liquid to a drainmast, whereat the liquid is ejected into the air during flight. Specifically, waste liquids are tapped into a common plumbing line leading to an outlet port on the drainmast. Accordingly, tapping the ice drawer""s drain line into the common plumbing line would seem to be the logical way to drain the ice drawer on a continuous basis. However, the waste liquids in the common plumbing line come from sources such as unfinished drinks poured down sinks and/or hand-washing water from the lavatory. Such liquid is commonly called xe2x80x9cgray water,xe2x80x9d in that it is no longer suitable for drinking but is not harmful to discharge into the air during flight.
If the ice drawer""s drain line was tapped into a gray water plumbing line leading to the drainmast (or other external drain), there would be a potential problem of gray water contacting previously potable ice. Specifically, in the unlikely event of a back-up, gray water in the plumbing line could back up through the ice drawer""s drain line and pass into the compartments of the ice drawer. This is clearly undesirable, as the gray water may not be suitable for drinking and thus should not be contacting ice cubes used to serve beverages. Therefore, if the ice drawer is to drain to the drainmast, a separate plumbing line and a separate ejection (i.e., outlet) port should be provided to assure sanitary conditions.
The present invention provides an aircraft drain device that can be used to drain an ice drawer to the drainmast (or other external drain) while assuring that gray water cannot enter the ice drawer drain line. In this manner, the ice drawer""s drain line can be connected to the common plumbing line leading to the drainmast. A separate plumbing line and/or a separate drainmast ejection port are not necessary to assure sanitary conditions and protection of the potable ice.
More particularly, the present invention provides an aircraft drain device for interposition between a potable water line and a gray water line leading to a drainmast or other external drain. The device comprises a first chamber and a second chamber, an inlet adapted for connection to the potable water line, an outlet adapted for connection to the gray water line and communicating with the second chamber, and a piston. The piston is movable within the housing between a normal operation position and a back-up operation position.
In the normal operation position, the inlet communicates with the first chamber and the first chamber communicates with the second chamber, whereby potable water within the first chamber may flow into the second chamber, through the outlet to the gray water line, and to the drainmast. In the back-up operation position, the first chamber is sealed from the second chamber This inter-chamber isolation prevents gray water in the second chamber from entering the first chamber, thereby protecting the potable water.
Preferably, the first chamber is vented, thereby providing an air gap between the inlet and the second chamber. This can be accomplished by providing openings in the housing so that the first chamber is open to the surrounding air. In any event, providing an air gap between the potable water line and the second chamber (whereat gray water can back up) is an industry-accepted and FDA-approved technique for protecting potable water. In fact, the present invention contemplates any construction defining an air gap, a chamber into which gray water can back up, and a seal between the air gap and the chamber should a back-up occur. It may be noted that the inter-chamber isolation (provided when the piston is in its back-up operation position) prevents grey water within the second chamber from spilling out of the drain device through vent openings.
Preferably, the piston is made of a material that floats in water. In this manner, back-up water in the second chamber will cause the piston to float from the normal operation position to the back-up operation position. To this floatation end, the piston may be made of lightweight material, such as plastic, and have a hollow construction. For example, the piston can be assembled from a cup-shaped component and a corresponding cap-shaped component.
Preferably, the piston, when in the back-up operation position, seals the inlet from the first chamber; whereby potable water in the inlet will not enter the first chamber. This isolates the potable water in an appropriate line. Also, should the first chamber be vented to provide an air gap between the potable water line and the second chamber, this inlet seal prevents leakage of the potable water through any vent openings.
Preferably, the piston seats against an inter-chamber seal to seal the first chamber from the second chamber, and seats against an inlet-surrounding seal to seal the inlet from the first chamber. The seals each may comprise a portion that moves upwardly after contacting the piston and seals therearound at a range of heights after such contact. In this manner, the inlet can be sealed first, followed momentarily by the sealing of the second chamber, or the sealed chamber can be sealed first, followed momentarily by the sealing of the inlet. In other words, precise, simultaneous sealing of the inlet and the chambers is not necessary with the present invention and/or the sealing of one chamber will not prevent the subsequent sealing of the other chamber.
These and other features of the invention are fully described and particularly pointed out in the claims. The following descriptive annexed drawings set forth in detail a certain illustrative embodiment of the invention, this embodiment being indicative of but a few of the various ways in which the principles of the invention may be employed.